


Give you something good to celebrate

by corsica



Category: Fate/Grand Order
Genre: Birthday Presents, Birthday Sex, Established Relationship, F/M, Fluff and Humor, Suit Kink, gratuitous use of formal wear craft essence outfits, in this house we stan suit karna, very nearly a PWP
Language: English
Status: Completed
Published: 2020-12-10
Updated: 2020-12-10
Packaged: 2021-03-09 22:47:34
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 12,606
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27984066
Author URL: https://archiveofourown.org/users/corsica/pseuds/corsica
Summary: It's Ritsuka's birthday. Not everyone knows.It ends up working out.
Relationships: Female Fujimaru Ritsuka/Karna | Lancer, Fujimaru Ritsuka/Karna | Lancer of Red
Comments: 6
Kudos: 24





	Give you something good to celebrate

**Author's Note:**

> this shit really was inevitable, i love that craft essence a whole lot even though i don't even have it rip
> 
> god please let me write something under 5k words
> 
> [also shout out to this comment on the fgo wiki page for karna's formal wear craft essence that kept making me laugh whenever i thought of it](https://fategrandorder.fandom.com/wiki/Heroic_Spirit_Formal_Dress:_Karna?commentId=4400000000000865926)

It was hardly the norm for her to climb on top of him first thing in the morning, her hands on his chest, fingers splayed out as she tried to kiss the air out of him, but there was little he could find to complain about, even less so as she urged one of his hands down between her legs and began to sweetly moan his name, speaking in dulcet tones about how wonderfully long his fingers were.

Karna kissed her through her climax, hand running up and down her back in a soothing motion as she fell against him, nuzzling her face into his neck. As he licked her taste off of his fingers, he could feel Ritsuka's soft lips pressing against his skin.

“That was a good way to start today.”

Her voice was a sleepy murmur. A pleased sigh passed through her lips as he took one of her hands in his own.

“I really, really just want to lie on you all day long, but...” she squeezed his hand.

It took her several minutes, but she did eventually manage to pry herself off the warmth that he offered, giving him one last, lingering kiss before she went into her bathroom to shower. Though he had _no_ _issues_ _whatsoever_ with what had just happened, he wasn't really sure why she had done it in the first place. Waking Ritsuka up before noon was an almost impossible task even on the best of days—it often fell to the Count of Monte Cristo to bring her cream, milk, and sugar that had at one point been coffee, and to guilt her into getting out of bed, utterly immune to her whining in spite of her best efforts, when Karna had already left her room hours earlier (caving _pitifully_ _easily_ to her whining)—but she seemed perfectly refreshed and alert this particular morning.

When she finally came out of her bathroom with a towel around her body and her hair dried and put up in the usual style, he was content to sit on her bed and watch her as she flitted around, dressing herself and getting ready.

“Alright!”

She clapped her hands together, then turned to look at him with a smile on her face. As she stepped closer to him, his knees spreading so she could stand between his legs, his arms wrapped around her waist while she cupped his face, tilting his head up to look at her. His lips parted as she leaned down to kiss him.

“Mh...” she pulled back from the kiss, her thumbs stroking at his cheekbones, “We probably won't see much of each other today, but I'll see you tonight, right?”

“Of course,” the question came off as somewhat strange—she saw him _every_ night; he shared her room with her, after all.

“Great!” she kissed his forehead, “I can't wait to see what you're wearing.”

Ritsuka missed the confusion that spread across his face as she broke away from him to turn and grab her light gray boots, holding on to a wall as she hopped towards the door while getting her shoes on.

“Hopefully I'll at least see you a little bit today,” she kicked her heel against the floor as her boot was fully on, “I'm so excited for tonight!”

She gave him a smile and a wave as she stepped out of her door, leaving him behind with the feeling that he was...missing something.

***

They _really_ hadn't seen much of each other, she hadn't been exaggerating. He had no idea what Ritsuka could've been up to that kept her almost entirely out of his sight. She hadn't been anywhere that he was all day.

Well. Almost anywhere.

He was coming back from an errand he'd been asked to run when he saw her standing with Lord El-Melloi II to the left in a hallway intersection, neither of them noticing him due to being deep in conversation about something. Curiosity piqued as he watched her, holding the _whatever it was_ that was in her hands, looking absolutely reverent.

“RX-78-02...!” she held it up in the light, and Karna could finally tell what it was: some sort of overly elaborate, large white robot, with blue and red decal, holding a giant shield and laser sword. In his head, he could hear her voice indignantly chastising him, saying _“it's called a_ Gundam, _Karna”._

“You helped me with my first few kits, so I decided to return the favor,” El-Melloi II scratched at his face, looking a little embarrassed, “I remember you told me that you liked Origin a lot, so I...”

“This...!” her eyes were sparkling in awe as she looked at him, “This is a _Perfect Grade!_ How long did it take you to put this together? _How much did you pay for this kit?!”_

“Don't...Don't worry about the cost. And as far as how time consuming it was, it only took me a few hours—I've gotten pretty good at putting them together quickly. All thanks to you, Ritsuka.”

Karna saw her eyes grow watery, welling up, fat tears beginning to roll down her cheeks, her crying turning into sobbing turning into outright inelegant blubbering. Ritsuka's face was buried snugly against his chest as she threw her arms around his waist in a clingy hug. El-Melloi II only seemed to become even more embarrassed, clearing his throat as he gave her a stiff pat on the back.

“ _Senseiiiiii thank you so muuuuchhhhhh...!”_

That had been the only time thus far he'd seen her actually get a gift, but would consistently overhear talk of giving Ritsuka things, and his confusion only continued to fester. He thought back as much as he could, but try as he might, he wasn't aware of any special holiday that landed on the day's date.

The cafeteria was full for lunch, as usual, and he could see Ritsuka sitting with Mash across the room, being approached by several different Servants: he'd watched as Achilles came up from behind her and ruffled her hair with a big, toothy grin on his face, and Ritsuka reacted with consternation, futilely swatting at him—her lips curled down into a pout as he handed her a small, wrapped package, but she took it anyway; she was still fixing her hair when a very anxious and _very_ flustered Ereshkigal shyly made her way up to her, index fingers twiddling together, her eyes moving off to the side as she said something to Ritsuka, who then yanked her down into a hug with a warm smile pulling at her lips—Ereshkigal's arms hung uselessly by her body and her face turned such a bright shade of red it was a wonder steam wasn't coming out of her ears; as Gilgamesh's child incarnation stood in front of her, smiling preciously, Ritsuka was positively charmed, and she kissed him on the forehead before visibly faltering when Gil happily handed her a...“dress” was perhaps not the best word for what he had given her—a more accurate description would be a piece of black fabric, long enough to be called a strapless dress only in the most charitable sense, that laced up all the way on both sides, the neckline leaving ample room for cleavage. The tips of Ritsuka's ears were a deep, burning crimson, and the innocent smile never left Gil's face.

There was a lull in the Servants that approached her, and he nearly turned back as Ritsuka began to eat her lunch once more, but the tension in his body skyrocketed as that nun, Kiara, went up to her, her presence utterly unnerving for reasons he didn't understand; he could feel the heat of Brahmastra behind his eye as she stopped in front of Ritsuka, ready at any second to defend his Master...yet all she did was lean down and gently place her hand on Ritsuka's shoulder, speaking to her with a smile that Ritsuka cautiously returned. More Servants continued to go up to her after that, but none inspired such intense, viscerally untrustworthy feelings as Kiara—not even Moriarity, who had walked up to her with a jovial laugh, saying something indecipherable and handing her a book that, from the distance he was at, he could just barely make out the words “Evil Schemes and You: Villainous Plots for Beginners” written on the front. Ritsuka had taken it graciously but seemed...less than thrilled.

His attention was finally drawn away—just as Nero stormed up to Ritsuka and boldly declared her greatness—by someone loudly clicking their tongue.

“Man, she's always gotta make a scene, doesn't she?” Mordred shook her head, shoving a few fries in her mouth before continuing to talk, “For someone who looks a lot like Father, she sure as hell doesn't act like him.”

“What's she giving Ritsuka—a...a small golden statue of herself. I...really should've seen that coming,” Sieg grimaced, “...At least it's not a weapon. Earlier, I saw Assassin Emiya hand her a pistol, tell her that it was loaded, and then walk away. That was concerning...”

Karna's brow furrowed, “What?”

“I thought some of the shit people were giving to her on Valentine's Day was insane—everyone is _really_ outdoing themselves today,” Mordred shook her head, just ignoring the whole “loaded pistol” thing, “Well, more weird stuff for her to have in her room, I guess. I'm too excited for the party tonight to care, anyway.”

“It does seem like it's going to be a lot of fun,” Sieg had a small smile on his face, and placed his glass of water down after he took a drink, “I was able to get a good look at the cake that the kitchen staff have been working on. I've never seen food that big before...”

“Oh man, I'm going to _demolish_ that thing later,” Mordred smirked, her sharp canines poking out as her teeth showed, “And hey, earlier today I taught her how to properly throw a punch as her gift; took her a little while but it was _all_ worth it when Merlin accidentally startled her and she slugged him across the face. Today is lookin' to be a pretty good day all around!” her smirk only widened, and her hands went behind her head as she leaned on the back two legs of her chair.

“Ah, I'm not really good at this kind of thing...I just ended up giving her some candy. She said it was her favorite a while back and she seemed pretty excited to get it, though, so I guess I didn't do too badly,” he looked at Karna, “I bet she'll love just about anything you get her, huh?”

Karna stared down at his hands, quietly putting his thoughts together, before he managed to meet Sieg's eyes with his own concerned, narrowed ones.

“...She has been receiving gifts from people all day. I can't complain about how well everyone is treating her—I feel the opposite—but...I don't understand the reason for it. There are usually specific days of the year for things like this, and there's nothing today that would warrant it.”

There was a pause. The cacophony of the cafeteria filled the silence. Sieg looked at him in mute shock. Mordred took a bite of her hamburger.

“Holy shit,” Mordred hadn't bothered to swallow her food before speaking, “You're kidding, right?”

Karna simply stared at her. Her eyes began to go wide as she realized, no, Karna was never _not_ sincere.

“Oh,” what little color there was in Sieg's face slowly drained away, “Oh, no.”

That wasn't a good sign.

“Today is her _birthday,_ you _dumbass Lancer.”_

His breath caught in his throat. A leaden feeling began to settle in his stomach as his blood turned to ice in his veins.

At least things made sense now, in the worst possible way.

“...I see.”

“There's...There's a big party being thrown for her tonight. Everybody is supposed to dress up nice. Um...” the grimace Sieg had on his face contorted into an expression of pure pain and sympathy towards Karna, “...She's been talking about how excited she is...to see what you've gotten for her...all day...long...”

Karna slowly squeezed his eyes shut, a look of agony recognizable on his face to those who knew him—and, as the realization sunk in further, recognizable to those who didn't.

“...I...see...” his voice came out deeply strained.

He peered up at a clock on the wall. How much time did he even _have?_

Sieg followed his stare, and laughed nervously, “The party starts in about six hours, so...you still have time, I guess...”

“Ha! Yeah, right,” Mordred could not have had less sympathy; amusement was present in her voice as she pointed at him, burger still in hand, “You're pretty fucked, aren't you?”

It sure felt like it!

***

Birthdays had never been...a thing, for him.

Most holidays weren't, especially now, given that many he had grown up knowing about no longer existed, but once he was contracted to Ritsuka, she made damn sure that he was involved in all of them once he knew what and when they were. She had even browbeaten him into telling her when his own birthday was—or rather, his best estimate of when it was, given the borderline impossible nature of converting the dates of the Dwapara Yuga he was born in to the modern calendar system—but he had given her an answer, and she insisted on properly celebrating it if he wasn't going to once it finally came around. Birthdays felt irrelevant to him as a Servant—more than they already did, anyway—given that none of them were capable of aging, but she was nothing if not adamantly, stubbornly persistent about it.

When the day had finally come, with her hand around his wrist, she'd dragged him willingly out of his room and into the empty cafeteria, passing by several confused Servants on the way, including his baffled half-brother, who had gotten a dull look and a small shrug as a response to his question of “what is she _doing”_. She'd sat him down at a table, had urged him to wait there, and had rushed past the door that led towards the kitchen that was visible behind the serving counter.

“I know it's only been about two months since I summoned you...” she'd spoken up from the kitchen, and his eyes had followed her as she'd moved around, putting things on a plate, “And I know there's nothing you could ever really possibly want—at least, nothing I'd be able to really get, but...”

She had walked out of his vision and through the door that led back into the cafeteria, carrying a plate of something. Once she had set it down in front of him on the table, she had gently bitten into her lower lip and had her arm behind her back, holding onto it. With her head tilted down, her hair had halfway obscured her face, including the nervous pink tinge on her cheeks.

“Um...I did my best...Raikou said that the final trial batch tasted okay, so...I, I know it's a pretty basic dish but I—I'm not that great of a cook when it comes to things that aren't Valentine's chocolates, so I didn't think I'd be able to make anything more complicated...” she had held her hands out, eyes wide and nervous, “If—If it's not good, you don't have to eat it! I won't be upset, I promise! And—And _please_ don't force yourself to eat it if it tastes bad just to make me feel better, okay? I can handle being rejected!”

It had been curry. Bright orange chicken, sprinkled with cilantro, had been split evenly in half from the white rice that had been slowly absorbing some of the orange color into itself. As the steam had wafted off the plate, he had followed it up until he had been looking at her face once more.

“Master, this wasn't necessary to do for me.”

Her hair had fallen towards her left shoulder as she tilted her head to the side with a small smile on her face. She had sat down across from him, folding her arms on the table.

“I kinda figured you would say something like that...but, Karna, listen. Today is supposed to be a special day for you, right? Even if _you_ don't feel like it should be, _I_ think you should have something nice for yourself today. And...hopefully I cooked that well enough for it to be that nice thing.”

He had taken pause, before finally picking up the fork next to the plate and taking a bite.

The chicken had been overcooked just a little bit, and there had been slightly too much salt and not quite enough garlic. The curry powder used didn't taste quite right, and neither did the rice. There had been just so many tiny, different things he could count that had made it much too dissimilar from anything authentic, discounting entirely the fact that it wasn't even made the same way now that it had been when he was properly alive, but it had been and still was one of the best things he'd ever eaten.

Karna had met her expectant look, and had swallowed down the bite he took.

“...It's good.”

He had watched her face slowly light up, eyes twinkling as a grin had grown across her face.

“Really?! Oh, I'm so glad. I was so nervous it wouldn't be edible, but...” she had given him the sweetest, most sincere smile, “Well...happy birthday, Karna.”

In hindsight, he'd realized that was when he'd fallen in love with her.

He thought back to that moment as he made the long walk to Da Vinci's workshop, in hopes of being able to see if the inventor had literally anything at all sufficient enough to give to her. Not knowing about Valentine's Day had been embarrassing, but this went _beyond_ embarrassing, being an utter disgrace.

As he rounded the corner, he'd been greeted with the surprise of Mash and Ritsuka speaking inside the workshop while Da Vinci puttered about, mostly ignoring them as she worked on something incomprehensibly mechanical behind her counter; he had been unable to ascertain what it was other than “large metal object with many screws”. The closer he got towards the two girls, though, the more he could tell it was less Ritsuka and Mash “speaking” and more “Ritsuka blubbering into Mash's chest even harder than she did earlier with Zhuge Liang”.

 _“Mash I love you so muchhhhhh!”_ she sniffed as tears rolled freely down her cheeks, and Da Vinci glanced over at her from the large metal thing she was taking a wrench to, shaking her head, _“I couldn't have asked for a better kouhai...!”_

“I—I'm glad you like it, Senpai!” Mash rubbed up and down her back while Ritsuka continued to cling to her, Mash's face lighting up in surprise when she saw Karna enter the workshop. Da Vinci herself waved at him, before giving whatever she was working on a firm _'whack'_ with her wrench, the noise loud and startling and utterly ignored by Ritsuka as she continued to hold onto Mash like a lifeline.

“So sorry! You'll have to give Ritsuka a minute,” Da Vinci teased.

He stared at Da Vinci before his gaze slowly panned to Ritsuka, his eyes narrowing in confusion, “...What...happened?”

Ritsuka was still bawling as she looked up at him, and she held up her arm; a purple and black chevron bracelet was around her wrist, “M-Mash made me a friendship bracelet to—to match the one I made her a while back. _It's so nice!”_ the bracelet disappeared from Karna's view as she wrapped that arm around Mash once more to crush her in a tight hug.

“S-Senpai, I can't...” Mash wheezed, and patted Ritsuka on the back, before her breath came back to her in a large sigh as Ritsuka finally pulled off of her. The ends of her long, white sleeves were damp from how much she had been wiping her eyes, eyes that were much more puffy than they had been when he'd seen her at the start of the day. He couldn't help how soft his features went as he looked at her; in spite of it all, she would always be beautiful.

Tears continued to slowly spill from Ritsuka as she went over to Karna, and he brought her in close as her arms wrapped around his midsection, her face buried in his chest.

“Karna...I love Mash so much...”

He stroked her hair while Mash covered her face in abject mortification.

_“S—Senpaiiii...”_

Ritsuka rested her chin on his chest, still sniffling as she gazed up at him, and he was able to see just how red-ringed her eyes really were. His hands rested on her head, thumbs swiping away at the few tears that continued to fall.

“F—For the most part, everybody has given me such amazing gifts today...” Karna met her lips as she stood on her toes to kiss him, “I can't wait to see what you've gotten me...”

Those words were like knives in his back, though she missed the excruciating look that appeared on his face as she tucked her head back into his chest to snuggle against him. Da Vinci, however, was not so blind, and her wide-eyed stare at him quickly shifted into an expression of smug amusement.

“...Well, I'm sure whatever it is, it'll be incredible~!”

Ritsuka wrapped her arms around his neck and pulled him down for one more kiss before leaving with Mash, and he could hear her start to cry again a little bit, to Mash's distress. The stare off he had with Da Vinci continued up until she was certain they were gone, and she shook her head with a sigh, regarding him sympathetically.

“She didn't tell you today was her birthday, did she?”

His eyes squeezed shut as pain flashed over his face, giving Da Vinci the answer she needed.

“Hoo boy, this is a bit of a mess, isn't it?” she leaned over on her counter, head tilting to the side, “I'm not sure if there's anything I can help you with on that front.”

“It's my fault. I can bear the responsibility.”

“I'm gonna go out on a wild limb here and say you didn't know about the party, either?” he shook his head, “Well, _that_ I can help with, actually. I can get you a suit made in no time at all—everybody is getting dressed up all nice for the fun of it. I, in particular, am going to look even _more_ beautiful than normal.”

“...Thank you. I don't know how I'll be able to repay your kindness,” he said, “There's not much I have worth giving to her...I'm at a loss for what to do.”

“Well, she loves those earrings you made, doesn't she?” Da Vinci crossed her arms, “Can't you just do something like that again? How much...magic sun god armor can you spare?”

“I'm not sure what I could...” he trailed off, looking down at his hands; as he did, his eyes narrowed, and an idea popped into his head, “...Wait...this is a selfish thing to ask, but...may I ask for your help on this once more?”

“Hm? Of course, it's no problem. What do you have in mind?”

He didn't respond, and simply manifested his armor.

***

“Oh—.”

Karna slid his arms into the suit jacket, looking over his shoulder as he heard the door to Ritsuka's room open. She blinked, standing helplessly, unable to do anything except stare at him, and he buttoned up the double-breasted jacket while watching her gradually become more and more flustered, up until she was covering the bottom half of her face entirely.

“You...” her eyes closed, and she averted her gaze down and away from him, “Karna, you look really good...”

Once he placed the red overcoat on his shoulders, given to him by Da Vinci along with the suit, he stepped over to her, gloved hands resting on her bare shoulders. Her hand finally came down from her face, a blush still covering her cheeks, and he could see her shiver as his fingers ran up to brush a lock of her hair behind her ear, eyes going wide and gaze turning tender as he saw her wearing the earrings he had given to her on Valentine's Day. Tracing back down her neck, his thumb stroked across the orange collar around her neck—he could see the color on her cheeks grow brighter, and he placed his hands back on her shoulders once more.

“I'm surprised you're not cold.”

“W-Well, I am a little bit, but...” she pressed her forehead against his chest, “...even your hair is all slicked down...This isn't fair, I didn't even know you had a suit that looked like that!”

“It was a gift,” his hands slid down to hold onto her small waist, and he leaned over, less so than he usually needed to given the heels she was wearing, to kiss along her bare shoulder.

Karna moved into her space until she was pinned up against the door, his fingers lightly gripping her chin to tilt her head up and kiss her. One of her hands touched against his suit, a quiet moan bubbling up from her throat, and she began to aimlessly trace against the fabric until she was stopped by his hand taking hers. When he pulled away from her, slowly, swiping his tongue over his lips, he saw that the redness on her cheeks had gone darker still.

His forehead was pressed against hers, and he stepped between her shaking legs, fingers dropping from her chin to curl one by one around her waist. The noise she quietly let out in response was somewhere in the middle of needy and distressed, repeating at a higher pitch as he kissed against her throat, above her collar.

“We...W-We should probably get— _nh,”_ she clutched at his suit with her free hand as he kissed down to the spot where her neck met her shoulder, “W—We should p-probably get going...”

Despite what she said, she didn't move, or tell him to move, her hand just continuing to run up and down his suit jacket, index and middle finger tracing against his tie. He gave her a moment before letting go of her hand to step back and away from her, and she reached for him almost reflexively—and as she realized what she had done, her eyes went wide, both of her hands going up to sheepishly cover her face as she shook her head.

“...” Karna couldn't help the mirth in his eyes, “...I hadn't thought that you would like it this much.”

Ritsuka simply groaned.

She dropped her hands from her face, inhaled sharply, and exhaled deeply.

“Okay...!” turning around so she couldn't get flustered just by looking at him—though Karna could see that her ears were still scarlet—she pressed the button to open the door, “L-Let's go!”

Though the flush on her ears had finally died down, he could still see it on the back of her neck during the entire walk towards the frankly decked-out room used to host the party. Ritsuka stepped forward in amazement, looking at the ornate golden walls, a stained glass chandelier hanging over the sparkling tile floor.

“This place looks incredible! Da Vinci said Holmes was the one who organized getting all this put together...how the hell did he do this?”

Ritsuka squinted and scanned the room, and a grin grew on her face once she saw Mash, heels clacking loudly against the floor as she broke out into a sprint. Mash squealed as Ritsuka all but tackled her, gleefully spinning her around.

“Mash!” she linked both of her hands with Mash's, “You look amazing! Where did you get this dress?”

“A—Ah, Senpai—!” Mash smiled at her, “Thank you! Um...I've had it for a while...I haven't really needed to bring it out until now. It was a gift from—from...ah...” Mash's face fell, and Ritsuka's excitement tempered as she figured out what Mash couldn't say.

“Oh, you...it's okay, I...I understand. It still looks really good on you,” Mash's cheeks turned pink as Ritsuka touched at the white flower in her hair, “This hairpin is such a nice addition!”

He stood off to the side, perfectly content to just watch Ritsuka, seeing her happily pull Mash into a dance before being whisked off by several different Servants who all wanted their own number with her—starting with Arthur, who had given her a smile and a gentlemanly bow as he asked for her hand to lead her in a simple ballroom waltz; Ritsuka had looked awfully proud of herself once they had finished for only having stepped on his toes two whole times, and Arthur congratulated her on her improved form. A polite invitation from the other Knights of the Round had subsequently followed—as polite as Mordred could get, at least—though once her dance with Bedivere was over, the requests became less and less chivalrous, eventually leading to Kiyohime simply swiping her while she was in mid-conversation with Marie to demand a dance and, by proxy, Ritsuka's attention focused solely on her.

She had slipped away from Kiyohime as soon as she was able to when the song had ended, rushing over to Karna for a moment of sanctuary.

 _“Help me,”_ she wheezed, “Nobody else besides the Knights of the Round seem to know how to dance. I thought Kintoki might be able to, but...I think he got too flustered by what I'm wearing. This dress is kinda low cut _and_ strapless...and I'm wearing a push-up bra,” she added the last part in a mumble, hands touching at her chest.

“It's also very short.”

“Yeah, that too...” she took in a deep breath, “Kiyohime really put me through the ringer on that, but I think she'll be satisfied for a little while, at least...” she wiped the sweat on her brow, “I think I just need to take a breather for a minute...”

“While you have the chance, then,” he started, moving a stray hair out of her face, “I would suggest going and speaking to Arjuna. He has been staring over here since you came up to speak to me...I think he's trying to be subtle...and if that's the case, he's doing a poor job. If he has yet to give you a gift, it's safe to assume that's what he wants to do.”

“Oh yeah, I don't think he has, yet...he tried to come up to me earlier but Eli, er... _asserted herself_ before he could say anything. I'll go see what he wants now.”

He leaned down to meet her kiss before she made the walk across the room to Arjuna, whose expression of calm calculation shifted into one of pleasant surprise as he saw her approach. They were too far away for Karna to hear, but he could see Ritsuka's face light up the longer the two spoke to each other, and her lips eventually spread into a cheerful grin as he placed something in her hand, which she put around her neck. Ritsuka held her hand up excitedly for a high-five that was returned, albeit awkwardly. As the song changed to a jaunty, exotic tune, he predicted the inevitable as he saw Quetzalcoatl rush up to her, yanking her away from Arjuna in her feverish haste. Whatever Ritsuka had been saying was cut off by a loud, echoing _“HRRK”_ sound.

“Oh, Master! This will be so much fun, yes!”

Arjuna was hiding his mouth behind his hand, but Karna was able to tell just how hard he was snickering as he watched Ritsuka get pulled into what was _supposed_ to be a samba, but ended up being something more akin to her being dragged around like a rag-doll, barely able to keep up due to both the pace and the height difference.

Ritsuka looked like she was ready to keel over from overexertion once Quetzalcoatl had finally finished with her, speaking a delighted “bueno, bueno!” as she clapped her hands, but any energy that had left Ritsuka returned threefold, her eyes bugging out and her jaw dropping as Boudica triumphantly wheeled out her cake. Karna's gaze followed hers, and he found that “cake” was perhaps not a generous enough descriptor of the five tier, shed-sized, mirror glazed, chocolate cake that had been decorated at each level with a repeating pattern of strawberries and white rosettes. The longer Ritsuka stared at it, the more incredulous she became, acting as if it was an unexpected Holy Grail rather than a birthday cake.

“Whew!” Boudica's long hair spilled behind her shoulders as she leaned around the cake to grin at Ritsuka, “Happy Birthday, Master!”

Ritsuka stumbled blindly over towards it, followed by a chorus of amazed and incredulous “oohs” and “aahs” from the surrounding Servants, and one prominent _“oh HELL yes”_ from Mordred. As Ritsuka stared up towards the cake, stupefied, she was joined shortly by Artoria, scanning it up and down in thorough analysis as she stood by her Master.

“Hm...” Artoria nodded, and summoned her sword at hand, presenting it to Ritsuka, “I believe this shall work fine in cutting the cake.”

Arthur's head tilted, hand over his mouth, brow a worried furrow, “I don't think Vivian would be pleased to see the sword being used in this manner...”

“S-Senpai, wait!” Mash was terribly fretful as she dashed up to Ritsuka, who had taken Excalibur and stepped back into a position better suited to cutting the gargantuan cake, eyes full of manic, childlike glee as she held the gleaming sword in her hands, “Artoria, are—are you sure it's okay for her to use that for...for _this?”_

“If doing so gets me a slice of that cake faster, I will let her do it a thousand times.”

Ritsuka glanced at Artoria, “I can't properly activate a Servant's Noble Phantasm, right?”

“That's correct.”

The words only made her grin harder. Very rarely had Ritsuka been _this_ giddy.

“...This light is the planet's hope...proof of the life that illuminates this world!” she held the sword straight up above her head as high as she could, _“Behold! **Ex...CALIBURRRR!!!”**_

Excalibur glowed and cleaved right through the cake, cleanly cutting it in half. Ritsuka was _extremely_ proud of herself.

Karna's eyes widened in slight surprise as he watched her come towards him with two slices—once she had finished miming a Noble Phantasm on the cake—and her head jerked towards one of the many round tables set out, a large bouquet placed in the middle of a white tablecloth on each of them. She plopped down, and kicked off her heels with a sigh.

“...When they said it was going to be big, I didn't think it would be _that_ big,” Ritsuka's eyes lit up, “But I got to use Excalibur! _I_ got to use _Excalibur!_ _I got to use Excalibur!_ I felt so cool!” she pumped her fists, “I looked cool, right?”

“You looked very cool.”

“ _Yeah!”_

His eyes were drawn to the simple silver chain around her neck, a small arrowhead hanging down to the middle of her chest. She made a surprised little noise as he touched against it, and she met his curious gaze.

“Was this...?”

“Oh! Yeah, I don't think I ever told you. You know how I asked Okita to help me learn how to use a sword, right? Because I didn't think I'd be able to use a sword bigger than a katana because...well...” she held up her thin arms, “I figured I should probably get a basic understanding of all the regular class weapons, so I asked Arjuna to teach me how to use a bow. To be honest, my first choice was Chiron, for obvious reasons—he is a _teacher,_ but Achilles apparently found out I was planning to ask him and um...” her eyes narrowed, “He was more than willing to talk Chiron up but also said that I would probably be killed, considering that his training is...kind of intense.

“I was going to ask Emiya after that but then started feeling guilty because I already ask him for help so much when it comes to cooking, so I just started running through a list of Servants and um...it might be called the “Archer” class but there are surprisingly few _actual_ Archers,” she glanced at him, confused, “Fujino-san...has psychic powers...I don't know how that makes her an Archer. But—that doesn't matter. Realistically, I probably should've asked Artemis, given she's the Goddess of the Hunt, but then I realized that would be a terrible idea. Thought about Arash...then I remembered when he catapulted me across a mountain in Camelot and decided against it. It eventually came down to Arjuna and Atalante...and I figured he'd be more patient with me.”

Karna closed his eyes for a moment, thinking back.

“...Is that why your arm was so red two months ago?”

“...Yes. I kept snapping the bowstring against my forearm,” she held up the arrowhead proudly, “But this is from the first arrow I managed to land against a target! It was right against the edge but it still hit—I'm surprised he saved it. I still think I like swordplay more, but not having to dodge coughs of blood during archery practice is a welcome change.”

The cheerful little grin she had on her face turned into a scrunched up expression as she stretched out her arms and legs and rolled her shoulders.

“Ah...it's nice to finally be off my feet for a bit. Getting dragged into all those dances was fun for a while but towards the end I was _literally_ getting dragged around. How was Quetzalcoatl able to dance like that in a yukata?” her fork went into the soft, spongy cake, “Well...at least she dressed up. Some people seemed to, um, misunderstand what constitutes formal attire... _Mh!_ Wow, this tastes _really_ good.”

“Atalante never struck me as the type of person to dress like that, but I guess I've been proven wrong.”

He took a bite of cake. It really _was_ good.

“Yeah, I—I don't...Blackbeard and Asterios are in their swim trunks? Where did they get the inner tubes... _why_ did they get the inner tubes...” she shook her head, “Most people dressed up really nice, at least. Mordred especially is killing it, she looks _amazing._ I wish I could pull off a suit as well as she does.”

“...I don't think I understand. I've seen the picture of you from Shinjuku. You looked nice.”

 _“Absolutely not._ That picture is _awful—_ I don't look cute in it at all! It didn't help that Jalter was forcing me to hold still while it was being taken,” she groaned, “Gh...whatever. At least this cake is amazing.”

“I had heard it was big, but it exceeded my expectations.”

“Apparently it took Emiya, Boudica, Raikou, and Tamamo Cat three days to make. I can't believe Emiya remembered what my favorite type of cake was,” she swallowed another bite, and he could see her eyes beginning to water, “Oh no...I feel like I'm gonna cry—I'm wearing mascara, I can't cry right now...”

His lips quirked up into a smile, “I don't think anyone here would be bothered to see you cry.”

“I know, but it's—Suzuka spent a really long time on my makeup and I don't want to ruin it!” she took in several deep breaths, and squeezed her eyes shut as she blinked back tears, “...Okay, I think I'm good.”

They stayed sitting for a while, giving Ritsuka the much needed down time she required, allowing the pain in her feet to slowly diminish. As she stretched her arms out over her head in a big yawn, plate in front of her having long since been reduced to nothing but crumbs, the lights overhead dimmed low, and a smooth, slow song began to play. Ritsuka hummed, and slid her feet back into her shoes to stand and offer her hand to Karna.

“Karna, come dance with me,” she murmured, “I've been wanting to, with you, for a while, but I kept getting grabbed by someone else.”

His features became gentle as he looked up at her, and he took her hand as he stood to full height, kissing against her knuckles. Ritsuka thoroughly scanned the room; no one was paying any attention to her for the moment, everyone off in their own little bubble or dancing with somebody else. Silently, she led him out of the room entirely, slipping into the hallway close enough for the music to still be audible.

He took her smaller hand in his as his arm wrapped around her waist. Her eyes closed, and Ritsuka rested her head and hand against his chest as they swayed to the melody.

“You know, last year for my birthday, I took a week-long trip to Hokkaido with my parents. We went up Mt. Hakodate...the view of the bay was one of the most gorgeous things I've ever seen. Later on in the week we stayed in Sapporo...I think Mt. Hakodate and the zoo we went to in Sapporo were my favorite parts. I liked the trip so much that I told my parents I wanted to go back again next year,” she lightly chuckled, “...I guess that's not happening.”

He squeezed her hand, and he heard her sigh into him.

“...I miss Dr. Roman so much,” his grip around her waist became firmer as he pulled her close against him, his face pressing into her neck, “It feels so strange, for him to not be here...I still expect to see him whenever I go into the command room...I still look for him when I go in there, before I remember...” she went quiet for a moment, “...It's especially strange, because Holmes has picked up a lot of the slack, doing some of the work Dr. Roman used to do and I've...caught myself calling him the wrong name. He's noticed...but he hasn't said anything. Kind of surprising, really...he's a bit of an ass, so I thought he'd mention something by now.”

She could feel Karna leave a soft kiss against her shoulder.

“At the very least...we stopped the Incineration of Humanity...even though, Mash...” he intertwined his fingers with hers as he felt her hand begin to shake, clasping it tightly until she was dragged out of her stupor, “Well...we sort of stopped it—there are those few rogue Demon Pillars out there. After we stop _that,_ who _knows_ what the U.N and the Mage Association have in store for us...”

Karna stopped swaying as she did, and his hold on her became loose as she broke away from his chest, her hand dropping from his. There was a nervous glint in her eye as she craned her neck up to look at him.

“...Listen, I...I don't want to sound spoiled, but...you still haven't given me anything...I don't think you've even said anything today at all, either...” she fumbled with her hands, her voice forlorn as her eyes drifted to the ground, “This sounds so selfish, but...Karna, I was really looking forward to seeing what you got for me...”

His mouth formed a thin line, and silently, he took a deep breath.

“...I have to confess, I wasn't aware that today was your birthday, and only found out mid-day. I never thought to ask...it was inconsiderate of me.”

Ritsuka stared at him blankly, her eyes slowly widening and the color draining from her face.

“Oh no, no no no no no, Karna I am _so sorry._ I never told you? I can't—I feel so stupid now! Why would you have gotten me anything if you didn't _know?!”_ she bit her lip, “I've been unintentionally guilting you about it, too...I'm so, _so_ sorry.”

The music shifted to something with a quicker tempo, the lighting coming back on, giving the hallway they were in a brighter glow. He reached up and tucked a lock of hair behind her ear.

“I was able to get you something,” his leather gloves were cool against her skin as he touched against her earrings, “Though I wasn't able to spend as much time on it as I had hoped to, I ended up being satisfied with how it came out. I hope you are, as well.”

He slipped his hand into his pocket, fingertips gently holding onto a golden ring that had three, very small, red gemstones embedded into it. Reaching for her left hand, it was a perfect fit on her ring finger, and he kissed against the back of her hand, before pressing his lips to each of her individual knuckles.

Ritsuka's breathing seemed to have halted entirely, her eyes blown wide and glistening as she pried her dumbstruck gaze away from her hand to look at his face.

“Karna, this...” her voice was small, in complete disbelief, as she trailed off.

“I struggled to figure out what to get for you on such short notice. When I spoke to Da Vinci, she brought up how much you liked the earrings that I...also made for you on short notice. However, I realized this could get across to you what I often have trouble putting into words,” he placed his other hand on top of her left.

She smiled at him, tears beginning to well up in her eyes, and she squeezed them shut to try and stop them from flowing out.

“...You have _got_ to stop using your armor for stuff like this,” she said with a laugh, and she shook her head, a small black smear of mascara rubbing off on her fingertips as she wiped at the corners of her eyes.

“It's a small sacrifice to make for you.”

Her arms wrapped around his neck as she pulled him down to kiss her.

“I love you, Karna,” she spoke against his lips, smiling beautifully at him when the kiss broke, her hands cupping his face.

Karna tilted his forehead down to let it rest against hers.

“...For as long as you are here, I wish to stay by your side, Ritsuka.”

It was quiet in the hall as he held her, hand tangled in the back of her hair, the music behind them switching to another soft and easy tune. The sweet moment between the two of them was dealt a bit of a blow as Ritsuka began to wiggle back and forth.

“...My feet _really_ hurt,” her voice was a petulant whine, “I think we should slip away quietly and go back to my room...I don't want to make a big scene and have to stand around another ten minutes while everyone has to individually give me their goodbyes. That would just make the pain _worse.”_

He nodded, giving her one last, chaste kiss before they left the party behind.

***

Ritsuka kicked off her heels with a huge, relieved sigh as she stepped past the threshold into her room, pulling her flowery hair tie out and tossing it in the general direction of her desk as Karna hung up his red overcoat. The collar around her neck was the last thing to be haphazardly thrown onto her desk—to be put away properly later—before she took off the arrowhead necklace and carefully removed her earrings to hang them back on their stand.

She struggled as she tried to reach for the zipper on the back of her dress, and she glanced over at Karna, ostensibly to ask for help, but any words she had begun to think of died before they could be spoken as the good, long look she was giving him turned into a leer. Her eyes went wide, and red flared up on her cheeks as she caught herself, forcing her gaze away from him, much too flustered, and Karna stared at her silently for a moment before he took the few short steps needed to close the gap between the two of them. As he stood behind her, he could see that the redness on her face had spread to the back of her neck.

“Today is supposed to be a special day for you,” Karna's voice was low and smooth against her ear; leaning down to kiss her shoulder, his fingers held onto her zipper and slowly pulled it down notch by notch, “Allow me.”

Fully unzipped, all it took was a little nudge, and her dress dropped onto the floor in an unceremonious heap. As his lips pressed against her neck, he held her chest in his hands through her strapless bra, enjoying the little hitch in her breath as he gently squeezed; teeth grazing against her pulse point, he undid the clasp of her bra, the exact same way she showed him how to during their very first time, so long ago, until it too fell, landing on top of her dress, leaving her in just her black pantyhose and underwear. She shivered as the cool leather of his gloved hands pressed against the now-bare skin of her chest as he cupped her breasts once more. A whimper quietly passed through her lips as his thumbs rolled over her breasts, growing louder as he sucked against a patch of skin on the base of her neck. Whimpers grew into outright moans of his name as his fingers began to pinch and tug and he cracked open his eyes during the brief period he stopped marking her neck to see her pushing up into his hands, rubbing her thighs together.

With one last kiss to her shoulder, he heard her gasp softly as he picked her up with little effort, walking the few paces towards her bed and setting her down at the foot of it, her legs dangling over the edge. He made the move to pull back, but her hand slipped around his tie, bringing him back down to kiss him. The look she had on her face when he pulled away was coy, and teasing—altogether much too pleased with herself. Karna gently pried her hand off, his own expression one of mild amusement.

He knelt down in front of her, his fingers going beneath the waistband of her tights as he began to carefully roll them down; smooth, creamy skin was revealed inch by tantalizing inch until they were finally off entirely. Once her legs were fully bare, tights tossed to the wayside, he kept her right foot held in his palm, treating her as if she was made of glass as he leaned down to lightly press his lips to the top in reverence.

Slowly, and as achingly meticulous as always, he kissed a path up her leg, palms cupping her knees to spread her apart as his lips made their way up, past her muscular calves and into the expanse of her thighs. He heard the sharp inhale of her breath as he nipped against her pale skin, leaving little marks along the inside of her legs that grew bigger in size and darker in color the further in he went. One of her hands moved from the white-knuckled grip it had on the edge of the bed to cover a soft moan as he sucked a mark near the crevice of her inner thigh, just a hair's breadth away from where the red lace on the edge of her underwear started.

As he had gone farther and farther inward, he was able to notice how the quivering in her stomach gradually became stronger. Even after all this time, she was still so shy.

“Ritsuka,” he started quietly, and his lips ghosted against her stomach before he gently urged her to lay down with the tips of his fingers, which she did; the damp spot on her underwear was visible for just a moment before he was sliding his fingers beneath the waistband to guide them down and off her legs, “I would like you to feel good,” a shudder went down his spine from the soft little _“oh”_ she sighed out as he lightly bit into the tender skin of her inner thigh, “So I will not stop,” another nip, even farther in, “Until you tell me to.”

His gloves dug into her thighs and he spread her legs wide enough until he was finally able to put his mouth on her. The gasp that came from her melted into a moan that she attempted to stifle by putting her fist against her lips, while her other hand snapped down to grasp at his hair, mussing it up. One of her legs came up high, knee bent, the heel of her foot resting against his shoulder blade as he pushed further into her, and Karna wrapped his arm around it, his hand resting on her thigh as he held her firmly where she was.

This was something he would never tire of. Perhaps it was a selfish desire, but her legs felt like they belonged around his shoulders.

He pulled her into him as his thumbs spread her wider, lapping at the slick that came out of her, tongue just brushing against her entrance. The brush turned into a gentle probe, and he savored how broken her breathing became the deeper he went, how her hips jerked as he increased his pace, catching as much of her sweet taste as he could. A disappointed whine came from her as he slowed, and he squeezed her leg apologetically.

Ritsuka's thighs trembled, and he gripped them harder as he flattened his tongue to give one long, gradual swipe up, a demanding and impatient moan of his name filling the room as he only just barely grazed against her sweet spot. Another sweep of his tongue, and the moan of his name he had drawn out from her this time was cut off with a sharp and airy gasp, a shock of pleasure running through her body from the feeling of what he had sucked between his lips, before he let it gently slip out. His fingers sunk divots into her thighs to keep her held open as he wrapped his lips around it once more, tongue dragging against it _slowly,_ and her breathing grew labored as he only continued to do it again, and again, faster, and faster. The hand she had grasping his hair was shaking, and he knew she only needed one last push—and a deep circling of his tongue was the push that did it.

A familiar tremor surged through her body as she softly cried out his name, hips twitching as he drank her down. He kissed against her thigh as he waited for her to catch her breath, listening closely to see if she would tell him to stop, and as her hand dug further into his hair, he got the answer he needed.

Karna's hands reluctantly came off from around her legs, and he bit at the middle finger of one of his gloves to pull it off before shedding the other one soon after.

“ _Please,_ Karn _nnh...!”_

The second the plea left her lips, he eased his middle finger inside of her. She shouldn't ever feel the need to beg—he needed to start doing better.

Satisfaction settled within him; the only noises coming out of her now were desperate little mewls wrapped around his name. As he put his lips back around her, and gently pushed his finger up deep inside of her, the moan on the tip of her tongue was replaced with a choked-off gasp, and any modesty she was still willfully clinging to was thrown to the curb as she grabbed his hair with both of her hands to pull him as close into her as she could, the slicked down look of his hair gone and back to its usual messy style from her fingers tugging at it; he could feel the skin on the back of his neck prickling as her fingernails grazed against his scalp.

The previous tension and apprehension in her body had completely evaporated as her hips shamelessly bucked into his mouth. His free hand slid up to hold her hip down, earning an agitated whine of his name in the process, but that melted into an unabashed moan poorly stifled by a bitten lip as he carefully worked his ring finger inside of her, his hand moving off of her hip to grasp at her thigh and angle her better once fully inside. Ritsuka's chest heaved, breaths all coming out of her as pleasured gasps as his fingers crooked up into her to stroke back and forth. He curled his tongue around her, could feel the muscles in her thighs go taut as her back arched up high off the bed. The slow relaxation of her body gave way to a series of needy whimpers, and the fingers she had in his hair were starting to shake once more; the only words she could even form was the soft and desperate mantra of _“Karna, Karna, Karna”._ She wouldn't be able to hang on much longer.

With a light increase of pressure from his fingers, he curved them up as his lips wrapped around her, and he could feel Ritsuka come undone yet again, pulsing around him. He kissed her shaking leg, and when she had reached the point where she had relaxed enough, he eased his fingers out of her, licking the shine off of them as she whimpered, mourning the lost feeling.

His hands clutched onto her thighs as he put his mouth on her once more, but he was met with a frustrated whine as his tongue worked into her.

“Stop stop _stop_ Karna get _up here_ already...!”

He pulled back to gradually raise up from his knees, his mouth marking its way up her body until he met her lips in a kiss that started as highly impatient on her end until she was distracted by his tongue meeting hers. Ritsuka's eyes had a glaze over them when he broke off, unfocused, a gorgeous red color spread high across her cheeks. Karna could feel her place her hand on his heart as he took her lips once more.

The suit was, at this point in the night, constricting and increasingly uncomfortable to keep on, but as he took a small step away from her, standing at full height to start undoing the buttons on the double-breasted jacket, he was stopped by Ritsuka protesting, weakly lifting herself up and grasping at his hand to stop him. She wrapped her fingers around his tie and brought him down to kiss him, head tilting to draw him into her as deeply and quickly as she could, a line of saliva still connecting them for a short moment when she finally pulled back, forehead touching his.

“Leave it on...” her voice was barely above a whisper, hot and breathy against his lips, “You look good, Karna...I want you like this...”

Her fingers fell limply from his tie as he kissed her, teasing out one whimper after another that he swallowed down, her bottom lip slipping out from between his teeth once he finally pulled away. Rustling the sheets, he unzipped his pants and watched as she turned over onto her stomach, up on raised elbows, her hair falling over one shoulder and she looked back at him, eyes silently, desperately pleading with him.

Ritsuka's breath caught in her throat as he pushed in, his hands resting on either side of her arms, his forehead resting against her shoulder, his body looming over hers as her back dipped in a perfect arch, her hips pressing back into him. Once he was able to open his eyes, he could see her twisting her sheets in shaking hands. The tiny, needy noises she couldn't help but make were held back just barely by her lips pulled into a tight, thin line, only to be replaced by a lengthy, relieved exhale as he finally bottomed out.

“I love you so much,” she whimpered, and he reached for her left hand, “D-Deep...” the cool metal of the ring had turned heated as he slotted his fingers between the spaces of hers, “Karna, _go.”_

Although he wished he could see her face, the sounds she made as he began to move his hips more than compensated for it. The discomfort he was feeling from wearing the suit was the last thing on his mind as he heard her brokenly whisper _“harder, Karna”,_ and those were the last few coherent words she said before he loyally abided her command, her voice slipping into breathy moans and cut-off whimpers of his name.

He could see her arms starting to shake as he broke away from kissing her neck, and it only worsened after a long, deep roll of his hips. Karna reached for her other hand and further slanted into her, nearly pinning Ritsuka to her bed. Another long, deep, _slow_ roll of his hips had her arcing her back and whining, and he gripped her hands more firmly as he did it again, in time with his teeth sinking into her shoulder, being rewarded with a choked-off moan as her forehead tilted to fall against her bed. Her hair curtained over her shoulders, around her face, and his lips pressed against the revealed skin of the back of her neck, down to the top of her spine, until small red bite marks were on every inch of skin above and between her shoulder blades.

Ritsuka's entire body was trembling beneath him; she had squeezed her eyes shut and caught her bottom lip between her teeth as she tried so hard to quiet the indecent moans that freely spilled from her throat. Karna released her right hand, giving her the freedom to begin twisting her sheets as an attempt to gain purchase once more, his fingers sifting through her hair to tilt her head just enough so he could gently, lovingly kiss above her temple before he snaked his arm down between her body and the bed to wrap around her torso, his grip around her left hand unbreakable. With one hard, fluid thrust, her lip slipped out from between her teeth as she cried out his name in an obscene, keening whine, fingernails clawing into her bed, tears prickling at the corners of her eyes. He did it again, feeling her writhe against him, sobbing his name like a prayer.

Once her furrowed brow started to relax, her eyes still closed in blissful pleasure, she moved her right hand to rest over Karna's, her fingers slotting between the spaces of his, and Ritsuka heard his quick, quiet breathing stagger as she clenched around him. She did it again, feeling his hold on her tighten, his fluid pace faltering.

Her arm slipped from atop his to rest limply against her head, but as his right hand slid down between her legs, his fingers spreading her apart, Ritsuka cried out, hand snapping back down to wrap around his wrist as his middle finger pressed in to rub circles against her. She was only scarcely cognizant of his lips pressing against the top of her head, and as his hips snapped inside of her, even that small bit of clarity was replaced by a dense and heady fog.

Karna felt her back arch once more, felt her hips grind back into him once more, felt the trembling of her whole body grow intense once more. She pressed her mouth against the bed to muffle herself as he hit deep inside of her with every thrust, while the grip she had on his wrist grew lax as his fingers worked more insistently, even as the rest of her body was tense and pulled taut. Every sign pointed to her being close, so he squeezed her left hand and kissed against her neck as he completely pinned her down to her sheets beneath him.

He kept his lips pressed against her temple as he angled a deep roll inside of her, his fingers dragging up against her; her body was so tight, practically vibrating. One more roll, one more drag, and the sound of his name that was drawn out of her was much too loud to be stifled in the slightest.

Ritsuka's left hand clutched his tightly as she peaked, her chest heaving as her breaths came out in hard and heavy gasps. His right arm wrapped around her stomach, and he left soft, slow kisses against the back of her neck and shoulders as he waited. The firm grip she had on his hand gradually lessened until she was pliant beneath him, breathing stabilized even if her pulse was still fluttering; he kissed against the side of her head again, lingering, before kissing her again, and he squeezed her hand as he kept it held in his.

Before he could do anything, he felt her fingers weakly touch his.

“Just because it's my birthday doesn't mean I don't want you to finish,” she mumbled sleepily, “Don't stop...”

He kissed the back of her neck before removing himself, to her confusion, and gently turning her until she was on her back once more, face red, arms slightly splayed out beside her. Ritsuka's eyes closed and she chuckled, just a little, and a fond smile grew on her lips as her hands reached up to his face.

“...Come here, Karna.”

One of her hands touched against his cheek, thumb stroking against the light crimson that was blossoming on both, while Karna caught the other one, eyes half-lidded as his gaze on her stayed unmoving. He could feel his heartbeat echoing in his ears as her palm cupped his face _._

_I love you more than you'd ever be able to understand._

Ritsuka whimpered into his mouth as he pushed back inside of her, one arm wrapping under her back and pulling her flush against him, the other grasping for her left hand and intertwining their fingers. Though her legs were still shaking, she was able to lock them around his waist as his hips snapped against her, her free hand carding through his hair, his tongue inviting her to make sweet, honeyed noises. As he tried to pull away, she tugged onto his tie again to kiss him once more before he was able to get too far.

“This thing is pretty handy,” she hummed, but it morphed into a moan as he moved down to suck against her neck, “Y-You look _amazing...”_

Karna broke off from Ritsuka once he left another mark of his teeth in her neck so he could get a proper look at her; she was staring at him with unfocused eyes and scarlet cheeks, her hair messy and haloed around her, her neck and chest covered with splotchy red marks and his teeth prints. The sound she made as he sucked at the skin beneath her jaw was one he closed his eyes for to better savor.

“As do you,” his breath was warm against her ear, and a sharp whine bubbled up from the back of her throat as he took her earlobe between his lips.

A gentle heat was against his face once more as she placed her hand on his cheek to urge him down for a kiss, and she bucked up her hips once their lips touched; he couldn't stop the small, but audible, grunt that spilled out, and Karna was able to feel the curve of her playful smile against his lips before she was coaxing his mouth open, moaning against his tongue. Ritsuka clung her legs around his waist tighter as he drew back, her fingers lovingly running through his hair as she watched his eyes shut and his brow furrow, and she pressed her lips against his forehead tenderly. The ring he had given her dug uncomfortably into his hand as he clutched hers as firmly as he could without hurting her.

She sifted her fingers into the back of his hair as he buried his face into her neck, and she bit her lip as his hips jerked against her. Ritsuka exhaled and felt her legs drop from around his waist, her energy utterly depleted, and she gave his left hand a loving squeeze when she noticed how much it was shaking.

As he finally drew back from her, he loosened his hold on her hand until he released it entirely, and she was free to use both to smooth his messy hair out of his face and eyes. When she was properly satisfied with the job she'd done, she cupped his face and brought his lips against hers for an affectionate kiss, unhurried in its pace. Gently, he took one of her hands to help abate the trembling in her fingers.

Ritsuka made a tiny, displeased noise when he broke the kiss, which turned into a whimper and a wince as he pulled back from her entirely. A sigh left Karna as he at last began to shed the suit, his armor re-materializing as he loosened the tie with one finger. Leaning up to see him, Ritsuka reacted predictably.

 _“Noooo...!”_ Ritsuka whined, “Don't take it off, you look so handsome!”

“...Do you think I won't keep it?” his eyes narrowed in slight confusion, and they flicked down to her hand, the ring on her finger glinting a little in the dim light, “I have to confess...it's very uncomfortable, but if you like it this much, I don't have an issue wearing it again for you,” his mouth formed a thin line, “Though I can't say I understand the appeal.”

“It just...it looks _really good_ on you, Karna. You like it when I wear certain clothes, too...” she sat cross-legged on her bed, a mischievous smile appeared on her face, “Do I need to remind you of how often I saw you staring at me the first time I wore the Atlas Academy Uniform in front of you?”

“You look nice in glasses,” he paused as he divested himself of the jacket, and he added in a mumble, “...and your legs look nice in stockings.”

Ritsuka's arms went behind her to prop herself up, and her eyes lit up in delight.

“Sorry, I didn't quite catch that?” all of her hair fell to one side as she tilted her head, “Were you talking about the time where, after we had been on that rayshift all day where I had been wearing the Combat Uniform for the first time, I noticed how flustered you were when we got back to my room and you asked, _very politely,_ to take me against a wall?”

His eyes closed, a red tint on his cheeks, “...You've made your point.”

Karna breathed out a small sigh once he completely divested himself of the suit, giving his shoulders a roll. Moving closer to Ritsuka, he picked her up once she uncrossed her legs, hearing a light giggle when he kissed her on the neck as he carried her to the bathroom. He was hesitant to set her down, especially given how, with just one foot on the bathroom tile, her leg was already shaking like a leaf. When she was finally, more or less, completely standing, he wrapped one arm around her stomach, holding her up easily as he reached for the shower nozzle to start cleaning her off.

He kissed a slow line up her neck as the water ran down her skin, “Do you want me to run the bath?”

“N...No, I don't think so. I just kind of want to get clean right now,” her grip on the nozzle was weak as he passed it to her, his hand going down and fingers spreading her apart as Ritsuka began to clean herself, “Nnh...it always feels weird coming out...”

“You insist on it. I wouldn't do it otherwise.”

“Weird doesn't mean _bad,”_ she huffed, and her nose wrinkled as she felt it run out of her, “I like knowing that you...that you're enjoying yourself. This is a small sacrifice to make for you,” she squeezed his hand and smiled as she felt him kiss her temple, “Besides, if I gave you entirely free reign, you'd use only your mouth on me for a solid hour and then be done.”

A big sigh of relief came from her once she had completely cleaned herself off. Karna didn't say anything as he grabbed her towel, arm moving to let Ritsuka wrap it around her body. When she carefully turned herself around to look at him, she saw him with his eyes closed, deep in thought.

“...Karna?”

“...No, I'm sorry,” his eyes opened, “One hour is too low of an estimate.”

She blinked, taking a moment to let what he just said sink in, before spluttering incoherently as her eyes widened and her cheeks grew red.

“What the f—what are you—how long could you _go?!”_

His eyes closed once more, yet again deep in thought.

“I'm not sure...it depends entirely on your own endurance,” his eyes opened, “I recall during a past summoning I was able to survive for a week with fatal damage to my spirit core without any proper healing...something like this, though, the energy needed would be significantly less,” his gaze was serious as he stared at her, “I think, in theory...I could probably last several months.”

Ritsuka couldn't even say anything.

It took her brain a hot second to kick back into gear after _that_ little confession, but once it did, she breathed in, breathed out, and placed her hands on his shoulders.

“You know what? Let's not test that theory.”

Karna's eyes closed once more, his demeanor solemn. He looked _disappointed._

“...I understand.”

She started to take a single step back towards her room, but she instantly lost all strength in her legs, being caught quickly by Karna before she could go tumbling to the ground. The tips of her ears were bright red, face the same color, and she sighed.

“You really don't ever want me to be able to walk the next day, do you?” she turned to stare at him, still flushed.

“It isn't intentional,” he paused, helping to right her, “...but if you could...it would feel like a failure, somehow.”

Her shoulders began to shake as she laughed.

“I guess I shouldn't be surprised that you're so thorough,” he placed his hand against her cheek, and Ritsuka nuzzled against it, “Well, look forward to carrying me around tomorrow, yet again.”

He leaned down to kiss her as she grabbed for his other hand, and he tilted his forehead against hers once their lips broke apart.

“...Happy Birthday, Ritsuka.”

She didn't say anything in response, but the smile she gave him made his heart beat faster, and as their fingers linked together, he could feel the metal ring against his skin as his hands held hers.

**Author's Note:**

> i dont know anything about gundams.
> 
> i'm trying to see just how far i can go writing (gratuitous) smut without making any reference to sexual organs because i find most words used for them just so viscerally repulsive. the word nipple is not attractive.
> 
> also, in general since i can't write arjuna for shit he exists purely for japes and i basically always write him as if he's post second interlude where ritsuka gives him a pamphlet on EMDR techniques and a bottle of xanax and tells him that having a negative thought once in a while doesn't mean he's lucifer incarnate. would love to pull him so i could know how to write him and subsequently write about the ot3 and their competition of Which One Of Us Can Dick Down Ritsuka The Best, but right now since i'm writing him as not having feelings for her, i basically see their relationship as [this picture, mutually, to each other](https://media.urbanistnetwork.com/saigoneer/article-images/legacy/PFPTzy0b.jpg)
> 
> anyway i love that karna and arjuna are technically capable of interacting semi-normally as seen in the first nero fest but basically don't because arjuna is almost always in "i am going to beat you to death with a hammer" mode and karna is almost always in "oh he doesn't understand what a video game is i will explain it to him while ignoring everything else he said including the part about beating me to death with a hammer" mode. 
> 
> and lastly i am probably the only person who actually both enjoys apocrypha (even though the story took a nosedive and became a slog after chiron, karna, achilles, and atalante died) and sieg as a character even though i think his romance with jeanne was dumb and bad and the two of them work fine on their own but as characters when put together they are charisma black holes but i see the apocrypha servants i have and i think "they r all friends :)"


End file.
